Expansion of the highway systems disrupts animal habitat and migration. Highways present a barrier to animals. Animals attempting to cross a highway subject themselves to potential death and can create a hazardous condition for the driving public. Disruptions in migration caused by refusing or being unable to cross the highway barrier cause population fragmentation. Culvert systems are installed in new roadways to prevent flooding and facilitate water passage. These culverts however remain dry much of the year and are used by many animals to safely cross the highway. At certain times of the year however, the presence of water in the culverts prevents small animals from passing. Further, certain animals do not use culverts for travel because the culverts do not present the proper environment for passage. Providing a safe pathway for year round movement of animals across a highway would preclude the need for animals to traverse the dangerous highway surface.